Electron discharge device of the magnetron type



June2'9, 1948. L.. A. WILLIAMS Emerson DISCHARGE DEVICE oF THE MAGNETRON TYPE 2 Sheets-Sheet 1 Filed Oct. 27, 1944 June 29, 1948. A. WILLIAMS ELCTRON DISCHARGE DEVICE F THE MAGNETRONTYPE Filed 001". 27, 1944 2 Sheets-Sheet 2 Patented June 29, `1948 ELECTRON DISCHARGE DEVICE F THE MAGNETRON TYPE Louis A. Williams, Belmont, Mass., assignor to Raytheon Manufacturing Company, Newton,4 Mass., a corporation of Delaware Application October 27, 1944, Serial No. 560,637

(Cl. S15-39) 4 Claims.

This invention relates to electron discharge de vices, and more particularly to those, such as magnetrons, for example, in which the frequency of the oscillations generated by the device is determined by the dimensions of the internal structure. im,

One of the objects of the present invention is to provide a device of theabove specified type comprising improved means for adjusting the device so that it shall be resonant at any frequency desired within the range of frequencies for the generation of which the device is designed. Y

Another object of the present invention is to provide a device of the general type referred to comprising means for readjusting the device to justing means.

These objects of the present invention, and such others as may hereinafter appear, will be best understood from the following description,` taken in vconnection with the accompanying drawings of embodiments of the invention hereinpresented for illustrative purposes.

In the drawings:

Fig. 1 is a top plan view of a device incorporating an illustrative embodiment of the invention;

Fig. 2 is a vertical section on line 2-2 of Fig. 1;

Fig. 3 is a top plan view of the device shown in Fig. 1, certain parts being brokenaway to show the structure underneath;

Fig. 4 is a plan view of one of the laminae;

Fig. 5 is a perspective View of the tuning member;

Fig. 6 shows illustrative means for the remote control of the invention;

Fig. 7 is a sectional detail showing a substitute device for the ball bearing;

Fig. 8 is a top plan view of a modification of the locking member for limiting the adjustment of the tuning member; and

Fig. 9 is a vertical section on line 9-9 of Fig. l, on an enlarged scale.

In the drawings an illustrative embodiment of the invention is shown as incorporated in a magnetron, said magnetroncomprising an envelope structure l forming the anode of the magnetron. This anode structure is made up of laminae 2 and 4, each formed with a central openingl and a plurality of radial slots 8 (see Fig. 4) each of which terminates in a circular opening l0. The laminae 2 are of smaller diameter `than the laminae 4 and sai-d laminae 2 and 4 arestacked or superposed one upon another alternately, the laminae 4 thus projecting beyond the laminae 2, the projecting portions of the laminae 4 forming cooling ns for the` magnetron. `Said laminae are preferably stamped from some suitable con,- ductive` sheet material, preferably from sheet copper. The laminae are soldered to each other with the corresponding openings therein aligned, thus forming a central bore constituted by the central openings 6 for the reception of a cathode, and aplurality of other bores corresponding to the openings IU. The slots 8 are also aligned, thus forming radial passages interconnecting said central bore with the plurality of surrounding bores. Silver solder is preferably used for soldering the laminae together.

Said envelope structure is hermetically sealed at one end by a cap I2 soldered in place tothe edge of said envelope structure I. At the other end said envelope structure is hermetically sealed by an annular member I4 (see Fig. 2) soldered at its edges to the edge of said envelope structure I and'provided centrally with a circular metal diaphragm I 5 hermetically sealed at its edge in said annular member. Said diaphragm will preferably be undulated to increasethe eX- tent of its transverse yielding movement. A screw-threaded stud I6, preferably of copper, is soldered to the outer surface of said diaphragm centrally of the latter, and has screw-threaded connection with a metal disc I8 having a groove 20 in its edge to receive balls 22 of a ball bearing,

of Which the other ball race is formed by two thin annular plates 24 having bevelled edges to receive the balls and held in place in an annular depression provided in the outer surface of said annular member I4, by a thin at spring annulus 26 (Figs. 2 and 3), clamped in place by a relatively thin nat metal ring 28 secured to thelmarp may be provided With a knurled disc 40 (see Fig. -2). A flatannular member 42 (see Figs 2 and 5) l member 42 toward or from the` anode structure as the case may be, thus to increase or decrease; the frequency, as will be hereinafter lmore fully. explained.

A cathode 50, preferably of the indirectlyA heated thermionilc type, is provided with an outer conducting sleeve 52 of suitableconductive material, nickel for example, coated with an e1ectron.`

emissive coating, such as.. barium and strontium oxides, and contains a heater 54. Said heater 5d is supportedwithin said sleeve 52 by having its ends extend throughinsulating blocks 56, 58 mounted in the opposite ends of said sleeve 52.

A lead-in conductor 62 is sealed through aglass seal 64, mounted at the outer end -of `a conducting pipe 'extending through thewall of said envelope structure l andhermetically sealed and fastenedtherein adjacent the'lower end thereof and is connected to the lower extended end of the heater 54. A second lead-in conductor 68 is sealed through a similarl glass seal mounted at the outer end of a conducting'pipe 12` likewise hermeticallysealed-` through the wall of said en velope structure I atfthelupper endthereof. The lead-in conductorf isconn'ected to the upper, extended end of the heater 54 and the latter is connected to the cathode sleeve 52 by a metal band 69. The lead-in conductors 62"and 68 carry lower andupper-shields Band' 6i', respectively,

of. tantalum, for example, to prevent electron .A

beams from being. projected. outwardly to the. cap` IZ'and` diaphragmv |15. Said lower shield Eil may also be connectedtothe cathode sleeve 52." By the above arrangement: the conductors 52 and'Y 58' may serve asthe heater current leads, said lead-inconductor falso: serving as the cathode lead; Said conductors. 621 andl S81 also serve to support thepcathode structure;

A. conductor pipe^14f (seei Fig. 3) ishermetically sealed through the:y side of the envelope structure l and extends into. the! interiorv of the magnetron. The outer end of said pipe 14 carries a .glass seal 16'throughwhich is sealed a lead-inconductor 11 having its inner endxconenectedito one. end* ofia coupling loop 18 in one;

of thebores formed' by the superposedV openings;

cathode. A capacity exists between said cathode and each of said anode faces 84. Capacitances also exist between the side walls of each of the aligned slots 8. The inner walls of the aligned openings I) constitute inductances. When the magnetron is energized and placed between pole pieces, such'as 8S and 38f(see Fig. 2), it generates oscillations as mentioned' above. The frequency of these oscillations is determined by the in- -ductances and capacitances above mentioned.

These-inductances; and capacitances constitute resonant circuits. It is desired that these circuits shall be resonant at denite predetermined frequencies V,withinthe-range of frequencies at which tl'ijedevice'- isv to operate. The device is intended to operate so that each oscillating cavity lil shall be tunedl tothe frequency at which each of the other ,oscillating cavities Il] oscillates.

According to my present understanding of the operation of the present invention, varying the positionof'y the annular -meinberz 42S relativelyV to the anode structure assaboV-e .mentioned will varyl the capacitances -of the anode'rstructure and.V con'-y sequentlyl-thei frequency of thel oscillations generat'edby thedevice, without affecting'v the inductances of said structure to the same degree. Thus I'. have: found that movement of;v .saidf `fiat annular 4member i2 towardi theV anode structure will` increase. the frequency, while movement'y of saidfannular -member'away from the'anodestructure will. decreasev the 'frequency'. "The: present invention; therefore enables the device to, be ad:- justed to generate oscillations of any frequency. within therange of: frequencies that the device can generate. Furthermore, if due .to` changes" in. temperature the. dimensions of? the .electron structure4 of the i device.r should-1 be soi changedi as.

to: change` the.V frequency4 from thatv desired', adil and thus is inductivelyf coupledA to onerofvv they.A

bores formed bythealigned openings'l in the. i

superposed laminae 24 and. 4. A second conductev ing pipe (not shown)y may be connectedv to saidz the anode structurecomprises a'plurality of subev stantially wedge-shapedarms82 (see Figs. 2rl and:A e), the faces 84 ofwhichare adjacent;the'cathode;'`

50i and cooperate as. anode.;.sections, with saidi from the .anode structure as thecasemay require; according.` as the change in: frequency.`- iszduefV t'o rise orto; fall irr temperature,y willrrestorethe. original: frequency.

Instead of the manual control of thetuning member, shown in Fig. 2, the.- contrlol: maybe ef;-

fected-froma distance.k Fig. showsillustr-ative means 'forthisi purpose comprising a smallire'fversible motor 9B of conventional construction, suppliedA .witir .electrical energy. from? l aA suitable source, not shown, andl controlled by a: convenx tional: reversing key 92 or other 'suitable means:

The shaft of saidrnotor maybe operatively con,-

nectedtoasaidshaft, as by'a flexible; shaftr 93= is provided upon its undersidaf,l around'v its edge,-`

withi a. thin 'rib'i91f.- This-:disc -94-risi-fplaced: in= ra depression provided on the; outer surface-'off an-` nulus. lv'4fand1 is;held: ini place: by,V said-resilient annulus: EEP-and clampingv ring-,Z-Slsecuredtof the end surface of said envelopelstruct-ure t byfstrews-` 30.. The rib 91 restsupona shouldeirA thusgreducing friction. Said disc 94isf no `thicker-thanthe; ball; bearing t8; 22, 24`and isA provided vwith three;-holessforrtheabove-mentionedlscitews; 3,4.5'byr which te fasten said discfto toothed' wheel 32.` i

The invention contemplates the provision of stud screwed into the cooling fins of the .de--

vice, as shown in Figs. 3 and 9. Arecess |04 is provided in the periphery of said disc 98 and a pinV |06 projectsv from the underside of said toothed wheel 32 near the edge of the latter. The arrangement is such that when the annular member 42 is at either extreme of its range of adjustment, said pin `Hitt will be in engagement with the edge of said disc 98 at one side or the other at said recess |04, as shownin dotted lines in Fig. 3, and said toothed wheel 32 will thus be locked against further rotation clockwise, viewing said iigure. If the said toothed wheel be now rotated contraclockwise, viewing said Fig. 3, the pin |06 upon reaching said disc 98 will register with and engage said recess |04 in the edge of said disc 98 and rotate it through an angle sufficient to free said pin |06, thus permitting further rotation of said toothed wheel in the same direction. When,`however, in such further rotation, the pin |06 again reaches said disc 98, said pin Will engage the edge of said disc and arrest further rotation of said toothed wheel, because, by the angular movement imparted to said disc 98 by engagement of said pin |06 with said recess in the rst revolution of said toothed wheel, said disc 98 was moved out of position to register with said pin. In the illustrative embodiment of the invention herein disclosed, only two consecutive revolutions of said toothed wheel in each direction are possible, that being suiiicient to permit selective adjustment of said tuning member to generate oscillations of any frequencies within the range of frequencies of said illustrative embodiment. In the case of a tube possessing a greater range of frequencies, it is only necessary to increase the number of recesses, such as |04, suitably spaced to allow, as it is revolved, said pin |06 to engage each of said recesses in succession before it is arrested, thus increasing the range of adjustment. In Fig. 8, for example, three recesses |04 are shown instead of one. It will be understood that each time said pin engages a recess, it moves the disc through an angle suiiicient to bring the next following recess into position to be engaged by said pin during the next revolution of said toothed wheel. In the revolution of said toothed wheel following that in which said pin engaged the last recess, however, said pin will engage the edge of said disc behind the last recess, thus arresting the adjustment.

The stop device, above described, precludes adjustment of the tuning member so close to the anode structure as to cause a short circuit.

A shield may be provided to protect said disc 98. Said shield conveniently comprises a semi-annular plate |03 partly overlying said disc and mounted upon said screw-threaded stud |00 by means of a supporting plate |05 parallel thereto and spaced therefrom by a rib |01, said screwthreaded stud 00 extending through holes in said circular plate |03 and said supporting plate |05 and being screwed in place by said screw-threaded stud I0. A spacing ring |09 is mounted upon said stud |00 between said semi-annular plate |03 and said supporting plate |05 and is provided at its top with a thin hub portion A spring washer 3 surrounds said hub portion so the underside ofsaid 6 that when said screw-threaded stud is screwed down into place said disc 98 will be clamped between said spring Washer and said plate |03 suiliciently tight to prevent accidental rotation of said disc 98, but not suiiiciently tight to prevent rotating of said disc when the recess |04 therein is engaged by said rotating pin |06, as close contact of said disc 98 withsaid ring |09 is prevented by engagement of the head of said screw-threaded stud |00 with the upper edge of said hub It will be noted that the space for the tuning member is obtained by eliminating that part of the top laminae within the envelope structure This and the compact structure of the ball bearing |8',`22, 24 keep the height of the device Within normal limits.

A protective' shield ||4, preferablyof transparent material, may be provided for the glass seals 64 and 10 secured by screws ||5 to a plate H6, said plate being secured to the cooling fins by a bracket and screws |8.

Whenever the expression a plurality occurs it is to be construed as meaning two or more.

I am'aware that the present invention can be embodied in other specific forms without departing from the spirit oressential attributes thereof, and I therefore desire that the present description be consideredin all respects as illustrative and notV restrictive, reference being had to the appended claims rather` than to the aforesaid description' to indicate the scope of the invention.

What is claimed is:

1. An electron-discharge device comprising: a cathode; an anode, including a plurality of cavity resonators, spaced from and surrounding said cathode; a iiexible diaphragm secured to said anode; a tuning member supported by said flexible diaphragm in spaced relation to said cavity resonators; a pair of threadedly-engaged, relatively-rotatable members, one of which is secured to said flexible diaphragm and the other of which is rotatably mounted with respect to said anode,

for adjusting the spacing between said tuning member and said cavity resonators; and a ball bearing intermediate said last-named relativelyrotatable member and said anode, said ball bearing including a race formed in said last-named relatively-rotatable member, a pair of springpressed, race-forming members carried by said anode, and bearing balls supported intermediate said race and race-forming members.

2. An electron-discharge device comprising: a cathode; an anode, including a plurality of cavity resonators, spaced from and surrounding said cathode; a ilexible diaphragm secured to said anode; a tuning member supported by said flexible diaphragm in spaced relation to said cavity resonators; a pair of threadedly-engaged, relatively-rotatable members, one of which is secured to said flexible diaphragm and the other of which is rotatably-mounted with respect to said anode, for adjusting the spacing between said tuning member and said cavity resonators; a ball bearing intermediate said last-named relativelyrotatable member and said anode, said ball bearing including a race formed in said last-named relatively rotatable member, a pair of springpressed race-forming members carried by said anode, and bearing balls supported intermediate said race and race-forming members; and means, journalled in said anode and engageable with said last-named relatively-rotatable member, for rotating the latter whereby said tuning member is moved towardlor away-fromgsaidcavity resonators.

3. `An electron-discharge :dev-icefcomprising: -a cathode; an .-anode, including va plurality of cavity resonators, spaced Vfrom and surrounding. said cathode; a exible diaphragm securedv to said anode; la tuning member supported by :saidexible diaphragm in spaced relation to said cavity resonators; a pair of threadedly-engaged, relatively-rotatable members, one oik which is rotatably-mounted with respect to said anodefor adjusting the spacing betweensaid tuning member and said cavity resonators; a ball bearing, intermediate said last-named relatively-frotatable member and saidanode, said kball .bearing including a race formed in said last-named relativelyrotatable member, a pair of spring-pressed raceforming members carried by said` anode, and bearing balls supported intermediate vsaid race and race-forming member; means, journalled in said anode and engageable with said last-,named relatively-rotatable member, for rotating thelatter whereby said tuning memberis moved toward or away from said cavity resonators; a pin oarried by said last-named relatively-rotatable member; and a cam member pivotally mounted on said anode and engageable With saidpin for limiting the movement of said last-named relatively-rotatable member.

4. An electron discharge device comprising: a 30 cathode; an anode, including aplurality of cavity :8 resonators, spaced from and surrounding said cathode; a ilexible member secured `to said anode; a Vtuning member supported. by -said exible member in spaced relation to said cavity resonators; means, operatively connected to said exible :membeig for adjusting the spacing between said tuning memlber and said cavity 'resonators; and means, including a pin carried by said adjusting means, and a cam having periphorally-disposed teeth carried by said anode 1and engageable with said pin, -for limiting the movement of said adjusting means.

LOUIS A. WILLIAMS.

REFERENCES CITED The following references are of record in lthe file of this patent: f

UNITED STATES PATENTS FOREIGN PATENTS Country Number Number Date Great Britain July 11, 1939 

